2.2. Engineering design

Engineering design also begins with a problem that points to an unsatisfactory situation which one wants to change into a more satisfactory one.

The model of the basic engineering design cycle is shown on the right in the next figure.

The research and design cycles

Problem

In the engineering design cycle the problem at the onset is that the facts are not aligned with our values and preference concerning these facts. And since (in the first instance) our values are unassailable, this discrepancy leads to us making it our aim to change the facts. We want to create a material condition which does agree with our values and preferences. This requires technical action. Technical action requires technical means, and these must be designed.

Analysis

Since design is aimed at possible, but not actually existing worlds, there is, initially, nothing to observe. But one can ask oneself in reasoning under what conditions a world that has been thought up will be both feasible and desirable. This process of reasoning takes place in the analysis phase. It often occurs that in analyzing a problem we come to the conclusion that we know too little to be able to carry out the analysis properly and that the lacking knowledge cannot be found anywhere. Then we have to make recourse to research, in order to fill the gaps in our knowledge. In doing so, the design process is left, strictly speaking. With the knowledge gained from scientific research, the design cycle is again entered, in order to further work on one or more possible worlds.

Synthesis

The synthesis phase in the design cycle is aimed at the totality of the entity to be designed, not only at a certain aspect, but at the entirety. A design is a kind of panoramic photograph, encompassing all aspects. Moreover, in designing (if we may talk of a photograph) we first have the photograph, and at a later stage (when the design has been realized) the object that was depicted. Synthesis in the design cycle is a priori (given before) the material reality which can be possibly realized. The pattern of reasoning in the synthesis phase follows the logical pattern of induction.

Simulation

The synthesis phase has yielded a provisional design for a product. Before we manufacture the product, we want to get an impression of how this product would behave if we manufactured it. We cannot be satisfied with merely one aspect, we want a comprehensive image of the behavior with respect to many aspects: functionality, durability, safety, usability, energy use, environmental consequences, cost price, etc. We would like to explore the possible worlds in which our product might occur before we make it into the real world.

Recapitulating, we can state that simulation in the design cycle leads to a conditional prediction of the behavior of the designed product, with respect to this product in its totality, that is to say with respect to as many aspects as possible.

At the beginning of the simulation phase we stand with empty hands. Thus we start the simulation phase, not immediately with deduction, like in the research cycle, but we first have to build up a logical system for that deduction. Since in designing, a number of aspects are involved, it often means that we have to construct a number of these deductive systems. Such systems are called models. Thus, at the beginning of the simulation phase, models should be constructed on the basis of which of the desired deductive operations can be carried out.

Deduction always takes place in a logical system. Logical systems belong to the domain of the mind (although they can be interpreted materially in books and the like). Some simulation models, for example mathematical models, directly form such logical systems within which deductions can be performed. Yet, many simulations call upon the help of experiments with physical models, which are considered, with respect to a certain aspect, as homomorphisms 1 of the original.

Thus we see that the simulation phase in the design cycle contains one element more than the deduction phase in the research cycle, namely the construction of a simulation model (or simulation models). The simulation phase in the design cycle often enters the field of material reality, via experiments with physical models.

Evaluation

During evaluation in the design cycle, comparisons are made between simulated design behavior and the desired behavior of the product to be designed. So factual statements are compared to value statements, resulting in value judgments as to the quality or utility of the design proposal, in the light of the design specification. Evaluation takes place entirely in the domain of the mind, largely in the domain of value judgments.

Decision

In the design cycle we encounter the element “decision” at this level. The decision aspect is expressed more explicitly in the design process. Here it concerns various possibilities to continue. First of all, the provisional design concerned can be improved in one or more iterations. The feedback arrows reflect this. But a decision can also be made to generate more design alternatives. The feedback arrows also clearly show this option. And finally, the decision can refer to choosing an attractive alternative from the collection of generated designs. The process ends with the yield of a number of acceptable designs, or – one decision step further – with the manufacturing of the most attractive design.

All of these designs are (irrespective of their often beautiful representations in drawings, mock-ups, scale models and the like) in the domain of the mind. Yet, that is not the intended final station, like knowledge in the research cycle. The design result requires to be realized in the domain of material reality, in order to leave the possible world in which it was conceived and to enter the factual world as a product. The design as a result of the design cycle is an intermediate station. It points to the realized product as a final station of the entire technological process, and that lies in the domain of the material reality.

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1

A homomorphism is a mapping between two structures that preserves the operations and relationships defined within those structures.